The Collaborative International Dictionary of English v.0.48:

ascendent \ascendent\ n.
   1. position or state of being dominant or in control. that
      idea was in the ascendant.

   Syn: ascendant.
        [WordNet 1.5]

   2. someone from whom you are descended (but usually more
      remote that a grandparent).

   Syn: ancestor, ascendant, antecedent.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Ascendant \As*cend"ant\, Ascendent \As*cend"ent\, a.
   1. Rising toward the zenith; above the horizon.
      [1913 Webster]

            The constellation . . . about that time ascendant.
                                                  --Browne.
      [1913 Webster]

   2. Rising; ascending. --Ruskin.
      [1913 Webster]

   3. Superior; surpassing; ruling.
      [1913 Webster]

            An ascendant spirit over him.         --South.
      [1913 Webster]

            The ascendant community obtained a surplus of
            wealth.                               --J. S. Mill.
      [1913 Webster]

            Without some power of persuading or confuting, of
            defending himself against accusations, . . . no man
            could possibly hold an ascendent position. --Grote.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

ascendent \ascendent\ adj.
   1. tending or directed upward.

   Syn: ascendant, ascensive.
        [WordNet 1.5]

              rooted and ascendant strength like that of
              foliage.                            --John Ruskin
        [WordNet 1.5]

   2. having the most important influence.

   Syn: ascendant, dominating, prestigious.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

ascendent
    adj 1: tending or directed upward; "rooted and ascendant
           strength like that of foliage"- John Ruskin [syn:
           ascendant, ascendent, ascensive]
    2: most powerful or important or influential; "the economically
       ascendant class"; "D-day is considered the dominating event
       of the war in Europe" [syn: ascendant, ascendent,
       dominating]
    n 1: position or state of being dominant or in control; "that
         idea was in the ascendant" [syn: ascendant, ascendent]
    2: someone from whom you are descended (but usually more remote
       than a grandparent) [syn: ancestor, ascendant,
       ascendent, antecedent, root] [ant: descendant,
       descendent]